(a) Field of the Invention
The present invention relates to a method and a device for sampling a radiation field emitted from an X-ray machine for the determination of certain operational characteristics of the machine. The device is in a cassette form whereby sampling of devices may be effected by the user of the device and analysis of the information contained in the cassette may be done at a central processing laboratory where the cassettes are forwarded by the users whereby to monitor the efficiency of X-ray machines.
(b) Description of Prior Art
In the prior art, various devices are known using X-ray Fresnel zone plates disposed to intercept an X-ray beam and an image receptor is disposed to receive the resulting image of the zone delineated by the X-ray beam. However, such devices are used for evaluating focal spots in X-ray tubes and do not provide for the evaluation of other important characteristics of an X-ray machine such as the dosage of radiation, the filtration efficiency of the machine, and the operating kilovoltage applied to the X-ray source or tube in the machine. It is medically established that frequent exposure to overdose of X-ray radiation is undesirable. This is particularly true in the dentistry field where the same patient may be frequently X-rayed and it is therefore important that these X-ray machines operate efficiently whereby radiation doses are kept to the prescribed amount of radiation.
Other prior art is known whereby an image is formed on an X-ray sensitive film showing density patterns (tones) corresponding to a series of energizing voltages furnished from an X-ray machine whereby these densities can be evaluated with respect to a standard film whereby to measure the radiant energy emitted by an X-ray machine to calibrate same. In all method known, the film is utilized with a screen which emits light to obtain an exposure and it is essential that the film be removed in a dark room.